Implement the command kill

[nuxlli]

Today if any error occurs in the execution of any command within the system of containers, the containers can happen to continue running and the user is left with no option to kill the process.

A kill command to accept as parameter the azk pid would be an option to force the kill of process.

This command must respect the --no-remove passed when creating the container.

[nuxlli]

For consistency the `ps' command no longer offers the option to automatically remove the container, would be an important new command that removes a container.